(CNN) --There was no sign that terrorism was involved in NASA's loss of contact with the space shuttle Columbia, Bush administration officials said Saturday.

"At this time we have no indication that the mishap was caused by anything or anyone on the ground," NASA Administrator Sean O'Keefe said in a news conference Saturday afternoon.

President Bush immediately left for the White House to address the crisis, a spokesman said. He was spending the weekend at the Camp David presidential retreat in Maryland, where he was briefed on the disappearance by his chief of staff, Andrew Card.

"The president has been informed about the situation. We are awaiting more information from NASA at this point," said White House spokesman Scott McClellan.

A senior law enforcement official, speaking on the condition of anonymity, told The Associated Press that the shuttle was flying at about 200,000 feet above earth when it disappeared -- well out of range of surface-to-air missiles.

"We have no information at this time that indicates that this was a terrorism incident," said Gordon Johndroe, press secretary for the Department of Homeland Security. "Obviously, the investigation is just beginning, but that is what we know now."

Security had been tightened for the January 16 launch because some officials were concerned that the presence of Israeli astronaut, Ilan Ramon, would make the shuttle a terrorist target. Ramon was the first Israeli astronaut to fly into space.

Vice President Dick Cheney, who was spending the weekend hunting in Texas, was briefed on the disappearance Saturday morning and was watching television along with receiving official updates, a spokeswoman said.

Homeland Security Director Tom Ridge is expected to oversee and coordinate the investigation efforts into the shuttle loss, even though terrorism is not suspected. Ridge joined other officials Saturday in the White House, where they were gathering more information about the crisis.

"We're all watching TV and devastated and concerned," John Marburger, head of the White House Office of Science and Technology Policy told the AP.